3 Sep 2010

First Isolation of the AsP3 Molecule

Literature Discussion

Submitted by Anne Bentley, Lewis & Clark College

Early in 2009, Christopher Cummins’ group at MIT reported (in Science) the synthesis of AsP3, a compound that had never been isolated at room temperature.  Later that year, a full article was published in JACS comparing the properties and reactivity of AsP3 to those of its molecular cousins, P4 and As4.  The longer article is full of possibilities for discussion in inorganic chemistry courses, with topics including periodic trends, NMR, vibrational spectroscopy, electrochemistry, molecular orbital theory, and coordination chemistry.

Microsoft Office document icon AsP3.doc50 KB
Learning Goals: 

After reading and discussing this paper, a student should be able to:

•    recognize the general names used for groups 15, 16, and 17
•    derive the expected number of Raman resonances for the AsP3 and P4 molecules
•    outline the trend observed in P–P vs As–P bond strength
•    compare the reactivity of P4 and AsP3 in at least one example and make predictions regarding As2P2 and As3P reactivity

Implementation Notes: 

This learning object was developed as one of five journal article discussions included in a small (5 student) senior-level inorganic course in the spring of 2010.  This course is the only inorganic course (aside from a separate inorganic laboratory) offered in our curriculum.

The literature discussions were interspersed throughout the semester.  This journal discussion was the final one in the semester, and we discussed questions 1-4 as a group before each individual presented the results of the reactivity studies they had chosen (question 5).  Student presentations were informal; it was a good opportunity for them to learn how to condense information.   

Time Required: 
30 minutes as implemented. A larger class might take more time.
Evaluation Methods: 

The students’ written answers to the questions and presentations of the questions were graded.

Evaluation Results: 

Because we discussed this article at the end of the semester, the stretching mode analysis was not fresh in the students’ minds.  They appreciated the chance to review earlier portions of the course. 

Creative Commons License: 
Creative Commons Licence


If you are interested in some fun context with this paper, I was at Gordon Conference when Kit talked about this work. He started off the talk with something like "I really hate meth-heads". P4 is impossible to buy now because it is a DEA controlled substance that can be used in the production of crystal meth. Humorous but also frightening.

hmm.  I guess I should lock up the approximately 200g of P4 we have in our stockroom.  Assuming its still there...

on a related note, try buying chemicals in California.  they have pretty strict rules and if the company doesn't have a physical location in the state, often you can't buy certain (presumably pro-drug) chemicals.  Some of the chemicals on the list are surprisingly benign...

This is quite scary, but funny. Let me check our stockroom....



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